Extreme pressure lubricant



Patented Apr. 8, 1952 UNITED STATES PATENT OFFICE EXTREME PRESSURELUBRICANT Oil Development Company, a

Delaware corporation of No Drawing. Application October 29, 19519,Serial No. 124,515

4 Claims. 1

This invention pertains to extreme pressure lubricants and compositionsfor imparting extreme pressure or load carrying properties tolubricating oils. The invention also pertains to a method for preparingextreme pressure agents which ample, certain machine elements such asthe hy-' poid gears commonly used in automotive vehicles may besubjected at times to extremely heavy pressures of the order of hundredsof thousands of pounds per square inch of bearing surface. If the filmof lubricating oil separating the opposed elements fails, that is, issqueezed from'between the opposed elements, as is likely to happen undersuch extremely high pressures, the surfaces of the opposed elements willcontact each other directly. This direct contact of the metal surfacesgenerates high temperatures due to friction which causes metal seizure,excessive wear, and early surface failure.

It is also known in the art that extreme pressure additives containingactive sulfur, phosphorus or chlorine alone or in combination whencontained in the lubricant used are effective for preventing theexcessive wear and early surface failure caused by the squeezing out ofthe protective oil film under heavy load conditions. The active sulfur,phosphorus, or chlorine react immediately with the unprotected metalsurfaces at the high temperatures generated to form a protective metalsulfide, phosphide, or chloride film. This film serves temporarily as alubricating medium until the normal oil film can be reestablishedbetween the metal surfaces. Extreme pressure additives are, therefore,reactive with. the metals they lubricate, forming extremely, thinprotective films thereon when the temperature rises due to the normaloil film failure.

It has been found, and is the subject of this invention, that excellentextreme pressure additives may be prepared by combining aphosphosulfurized fatty body with a halogenated nonvolatile organiccompound.

Accordingly, it is the object of this invention to provide a new anduseful extreme pressure additive for lubricating oils. A further objectof this invention is to provide lubricating oil compositions which haveexcellent extreme pressure and load carrying properties.

Briefly stated, this invention comprises incorporating into alubricating oil a mixture of a fatty body which has been treated with aphosphorus sulfide, and a halogenated non-volatile organic material.Although it is within the concept of this invention to use as oneingredient any oxidized fatty body combined with phosphorus sulfide, thepreferred embodiment of the inventio is phospho-sulfurized degras.Degras, the dark brown grease from sheep wool, may be phospho-sulfurizedby the procedure described below. The other constituent of the mixturecombined with a lubricating oil to make the ex treme pressure lubricantof this invention is a halogenated non-volatile organic compoundtypified by chlorinated wax, chlorinated kerosene, chlorinated naphtha,chlorinated oil, or a chlorinated methyl ester of tall oil, thepreferred embodiment of the invention being chlorinated wax.

The first mentioned constituent of the extreme pressure additivemixture, that is, the phosphosulfurized degras, may be made by reactingcommercially available degras, a Wool oil extract, with about 10 to 40%by weight, preferably about 18 to 25% by weight, of phosphoruspentasulfide (Pass) at a temperature of between 275 F. and 350 F.,preferably 300 F. It is convenient to carry out the reaction insolution, for example in a lubricating oil fraction, thereby obtainingan oil concentrate which may contain, say, about 30-70% of activeingredients. Degras has an oxygen content (by analysis) of 6 to 7%. Anexothermic reaction occurs and generally a reaction time of an hour orslightly less is involved. The temperature is above the temperature ofthe thicphosphate formation and may be carried out without theintroduction of any substantial amount of phosphorus into the. reactionproduct. However, if a lower temperature is used a thiophosphate may beformed. The phosphorus and oxygen-containing sludge may be removed. Thisreaction product, depending upon the proportion of ingredients and thetemperature used. will contain from 4 to 13% sulfur, and from 0.5 to 3.97'2; phosphorus, on the basis of a 50% concentrate.

The chlorinated non-volatile organic material used as the secondconstituent of the extreme pressure additive mixture of this inventionmay be made by any of the methods known to the art. For example,chlorinatedwax may be made by bubbling chlorine or a chlorine containinggas through a meltedwax until it contains from about 35 to about 65% ofchlorine. The same general procedure is used for chlorinating kerosene,aromatic heavy naphtha, a lubricating oil or other hydrocarbon which maybe used as the second ingredient.

These two constituents are mixed together in varying proportionsdepending upon the amounts of chlorine, phosphorus, and sulfur that itis desired to incorporate into the lubricating oil. The percentage ofthe sulfurized degras product may vary between 2% by weight and 15% byweight, with 10% being preferred. The second constituent of the mixture,that is, the halogenated nonvolatile organic compound, may vary between8% by weight and by weight, the preferred percentage being 5%.

To exemplify the concept of this invention, the following examples aregiven:

Three samples of phospho-sulfurized wool grease, prepared as 50%concentrates in oil according to the general procedure given above, gaveon analysis the following percentages of sulfur and phosphorus:

Per Cent S Per Cent P Product A. 7. 98 2. 51 Product 13 6. 70 1.09Product 0 5.01 1.00

2.5 percent by weight of the 50% concentrate Product A and '7.5% byweight of a chlorinated wax having a chlorine content of 40% wereblended in the base oil. The combination gave exceptional results in theSAE test and in the Timken test, and carried the maximum number ofweights in the Almen shock test. Data obtained on this blend, and onblends of the two additives employed singly are shown in Table I.

Table I EXTREME PRESSURE LABORATORY TESTS SAE Additive, Per Cent byWeight Test Timken figs in Base 01] 1000 OK Load W h R. P. M. t

2.5% Product A 7.5% Chlorinated Wax 335 15 10% ProductA 100 51 5 10%Chlorinated Wax 282 51 13 None 60 10 l EXAMPLE II Blends of the 50%concentrate Product B and (a) chlorinated wax containing 40% chlorine,(b) chlorinated Ca and C9 aromatic naphtha (mostly methyl and ethylderivatives of benzene) having a chlorine content of 28.8%, and (c)chlorinated methyl ester of tall oil having a ch1o-" SAE Test Almen TestAdditive Per Cent by Tlmkcn Blend wei htm Base Oil {2 OK Load ggf f 2.57Product B a {7.57; Chlorinated wax.-. 281 68 15 10% Product B b57hChlorinatcd Naph- 302 a. 10% Product B c 5% Chlorinated Tall Oil 3211 Not determined.

It will be observed from a comparison of test blends (a) and (d) thatsubstitution of a part of the chlorinated wax in blend ((1) with ProductB had little or no effect on the results obtained in the SAE and Almentests. It is noteworthy, however, that in the type of serviceexemplified by the Timken test, the performance was measurably improved,and that the combination carried the maximum number of weights in theAhnen Shock test. Product B was of course only a 50% concentrate, sothat these good results were obtained with a smaller total weight ofactive ingredients. In test blends (b) and (c) the proportion of ProductB was increased to 10%, containing 5% of active phospho-sulfurizeddegras and 5% of the chlorine-containing compound. The high SAE ratingsof J02 and 321 should be noted.

EXAMPLE III A lubricant comprising 10% by weight of phospho-sulfurizeddegras containing 5% sulfur and 1.0% phosphorus, that is, Product C, and5% by weight of chlorinated wax containing 40% chlorine in the test oilgave the following inspections:

Gravity 23.3 Flash point (F.) 4.45 Vis/ F 1002 Vie/210 F 87.9 Viscosityindex 94.6 Sulfur, weight per cent 0.86 Phosphorus, weight per cent 0.11Chlorine, weight per cent 2.44

When tested in the Copper strip test at 250 F., this material gave alight peacock color, which is a passing grade in the test.

This lubricant performed very satisfactorily in the CRC L19 (high speed)full scale automotive axle test. This is the Army ordnance departmentspecification test No. AXS-1569 designed to simulate highspeed'passenger car service. In addition, this composition also gavevery satisfactory performance in the CRC L-20 (high torque) full scaleaxle test designed to simulate low speed, high torque conditionsrepresentative of heavy duty truck service which is the ordnancespecification test No. AXS-15'70. Moreover, the lubricant performssatisfactorily in the G. M. Chevrolet dynamometer shock test (Federalspecification VV-L-761) a test designed to represent extremely severepassenger car service.

Most materials of the prior art give a satisfactory performance in onetype of service and poor performance under other types of operatingconditions. The composition of this invention, however, is unusual inthat it exhibits excellent all-purpose performance, giving satisfactoryperformance in all three of these types of service.

What is claimed is:

1. A lubricating composition which comprises a major amount of alubricating oil base stock and a minor amount of a mixture of about 2/2% to 10% by weight of a 50% oil concentrate of a P285 treated degrasanalyzing from about 5.01% to 7.98% sulfur and from about 1.0% to 2.51%phosphorus, and about 5% to 7.5% chlorinated wax containing about 40%chlorine.

2. A lubricating composition which comprises 90% of a lubricating oilbase stock, 2.5 weight percent of a 50% oil concentrate of a P2S5treated degras analyzing 7.98% sulfur and 2.51% phosphorus and 7.5weight percent of a chlorinated wax containing about 40% chlorine.

3. A lubricating composition which comprises 90% of a lubricating oilbase stock having blended blended therein 10% of a 50% oil concentrateof P285 treated degras analyzing 5.01% sulfur and 1% phosphorus and 5%of a chlorinated Wax containing about chlorine.

WALTER E. WADDEY. ELMER B. CYPHERS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,383,495 Musselman Aug. 28, 19452,468,031 Burk Apr. 26, 1949 2,468,520 Sproule et a1 Apr. 26, 1949

1. A LUBRICATING COMPOSITION WHICH COMPRISES A MAJOR AMOUNT OF ALUBRICATING OIL BASE STOCK AND A MINOR AMOUNT OF A MIXTURE OF ABOUT 21/2% TO 10% BY WEIGHT OF A 50% OIL CONCENTRATE OF A P2S5 TREATED DEGRASANALYZING FROM ABOUT 5.01% TO 7.98% SULFUR AND FROM ABOUT 1.0% TO 2.51%PHOSPHOROUS, AND ABOUT 5% TO 7.5% CHLORINATED WAX CONTAINING ABOUT 40%CHLORINE.